全文获取类型
收费全文 | 1115818篇 |
免费 | 95621篇 |
国内免费 | 22049篇 |
专业分类
耳鼻咽喉 | 14762篇 |
儿科学 | 26869篇 |
妇产科学 | 27986篇 |
基础医学 | 155227篇 |
口腔科学 | 29526篇 |
临床医学 | 112448篇 |
内科学 | 201371篇 |
皮肤病学 | 19243篇 |
神经病学 | 84381篇 |
特种医学 | 44495篇 |
外国民族医学 | 369篇 |
外科学 | 160179篇 |
综合类 | 68095篇 |
现状与发展 | 76篇 |
一般理论 | 289篇 |
预防医学 | 82339篇 |
眼科学 | 28531篇 |
药学 | 92061篇 |
299篇 | |
中国医学 | 17082篇 |
肿瘤学 | 67860篇 |
出版年
2022年 | 13294篇 |
2021年 | 18822篇 |
2020年 | 13792篇 |
2019年 | 14305篇 |
2018年 | 16736篇 |
2017年 | 14103篇 |
2016年 | 14424篇 |
2015年 | 19640篇 |
2014年 | 25712篇 |
2013年 | 29001篇 |
2012年 | 40899篇 |
2011年 | 44789篇 |
2010年 | 26607篇 |
2009年 | 22862篇 |
2008年 | 35446篇 |
2007年 | 37476篇 |
2006年 | 37693篇 |
2005年 | 37645篇 |
2004年 | 31657篇 |
2003年 | 30203篇 |
2002年 | 28084篇 |
2001年 | 40995篇 |
2000年 | 42390篇 |
1999年 | 37645篇 |
1998年 | 13783篇 |
1997年 | 13180篇 |
1996年 | 12068篇 |
1995年 | 11462篇 |
1994年 | 10557篇 |
1992年 | 28710篇 |
1991年 | 27798篇 |
1990年 | 27075篇 |
1989年 | 25895篇 |
1988年 | 24229篇 |
1987年 | 23750篇 |
1986年 | 22393篇 |
1985年 | 21634篇 |
1984年 | 16682篇 |
1983年 | 14172篇 |
1979年 | 16816篇 |
1978年 | 12114篇 |
1977年 | 10181篇 |
1976年 | 9328篇 |
1975年 | 10147篇 |
1974年 | 12641篇 |
1973年 | 12136篇 |
1972年 | 11538篇 |
1971年 | 10685篇 |
1970年 | 10218篇 |
1969年 | 9909篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
对于新病人。护理人员可为病人拟订护理计划并自己执行护理活动。但多数时间。护理人员是连续其他护理人员已执行的护理活动,因此交接班的好坏对护理质量有极大的影响。做好充分的交接班准备和一个能把握住重点的报告,可以得到真实完整的资料,使护理活动一开始就进入良好状况,保证原来护理工作的连续进行,提高护理质量。为此,2004年5月-2006年5月我科开始规范临床护理交接班工作,收到较好的效果。现将工作中存在问题进行分析并提出对策。 相似文献
992.
The absolute activities of the pure beta-emitters 89Sr and 90Y have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number of radionuclides that have been standardized by this non-extrapolation liquid scintillation (LS) method. Both measurements were carried out within the framework of international key comparisons under the auspices of the International Bureau of Weights and Measures (BIPM). The TDCR results agreed well with those of other participating national laboratories, most using alternative (tracer) methods. 相似文献
993.
Noriyoshi Kurihara Hua Zhou Sakamuri V Reddy Veronica Garcia Palacios Mark A Subler David W Dempster Jolene J Windle G David Roodman 《Journal of bone and mineral research》2006,21(3):446-455
We targeted the MVNP gene to the OCL lineage in transgenic mice. These mice developed abnormal OCLs and bone lesions similar to those found in Paget's patients. These results show that persistent expression of MVNP in OCLs can induce pagetic-like bone lesions in vivo. INTRODUCTION: Paget's disease (PD) of bone is the second most common bone disease. Both genetic and viral factors have been implicated in its pathogenesis, but their exact roles in vivo are unclear. We previously reported that transfection of normal human osteoclast (OCL) precursors with the measles virus nucleocapsid (MVNP) or measles virus (MV) infection of bone marrow cells from transgenic mice expressing a MV receptor results in formation of pagetic-like OCLs. MATERIALS AND METHODS: Based on these in vitro studies, we determined if the MVNP gene from either an Edmonston-related strain of MV or a MVNP gene sequence derived from a patient with PD (P-MVNP), when targeted to cells in the OCL lineage of transgenic mice with the TRACP promoter (TRACP/MVNP mice), induced changes in bone similar to those found in PD. RESULTS: Bone marrow culture studies and histomorphometric analysis of bones from these mice showed that their OCLs displayed many of the features of pagetic OCLs and that they developed bone lesions that were similar to those in patients with PD. Furthermore, IL-6 seemed to be required for the development of the pagetic phenotype in OCLs from TRACP/MVNP mice. CONCLUSIONS: These results show that persistent expression of the MVNP gene in cells of the OCL lineage can induce pagetic-like bone lesions in vivo. 相似文献
994.
J Thornton D M Ashcroft M Z Mughal R A Elliott T W O'Neill D Symmons 《Archives of disease in childhood》2006,91(9):753-761
AIMS: To evaluate the currently available evidence for the effectiveness of bisphosphonates in children with low bone mineral density (BMD) and fragility fractures associated with juvenile idiopathic arthritis (JIA), and the safety of bisphosphonates in JIA and other conditions. METHODS: Literature databases were searched using a structured search strategy. The effectiveness review included any studies of children with JIA treated with bisphosphonates. The safety review also included studies of osteogenesis imperfecta. Quantitative data analysis was not undertaken because of the heterogeneity of the studies; findings were summarised using tables and narrative synthesis. RESULTS: Ninety four studies were identified. Sixteen studies (78 JIA children) were included in the effectiveness review: one randomised controlled trial, three controlled cohort studies, 11 case series, and one case report. At baseline, children had low BMD below the expected values for age and sex matched children. In all studies, treatment with bisphosphonates increased BMD compared with baseline: the mean percentage increase in spine BMD ranged from 4.5% to 19.1%. Overall, studies were heterogeneous and of variable quality. A total of 59 papers were included in the safety review; treatment durations were up to three years. The most common side effect was a flu-like reaction with intravenous treatment. This occurred during the first infusion and was transient; the symptoms were managed with paracetamol and did not occur during subsequent cycles. CONCLUSIONS: Bisphosphonates are a promising treatment for low BMD and fragility fractures in children with JIA. However, the quality of the current evidence is variable and better studies are needed to more clearly assess their role. 相似文献
995.
L. van den Bemt M. P. de Vries L. van Knapen M. Jansen M. Goossens J. W. M. Muris C. P. van Schayck 《Clinical and experimental allergy》2006,36(2):233-237
BACKGROUND: Exposure to a high level of house dust mite allergens (HDMAs) is considered as a risk factor for HDM sensitization and development of asthma in genetically disposed people. Mattresses are one of the most important sources of HDMA in people's living environment. OBJECTIVE: The aim of this study was to evaluate the association between mattress characteristics and HDMA concentrations on mattresses. METHODS: Dust samples of mattress surfaces were taken to evaluate the level of Der p 1 allergen. All participants filled in a questionnaire about the type of mattress, the type of covering (upper layer) of the mattress, dwelling characteristics and cleaning habits. Humidity and temperature of the bedroom were measured at the time of dust sampling. RESULTS: One hundred and sixty-eight questionnaires were filled in. Synthetic upper layer of the mattress was associated with a higher level of Der p 1 compared with cotton upper layer (2.6 vs. 0.8 microg/g Der p 1). Moreover, higher relative humidity (RH) was associated with significant higher concentrations and density of Der p 1. CONCLUSIONS: Two factors were associated with lower levels of Der p 1 found on mattresses, namely: a cotton upper layer of the mattress compared with a layer of synthetic material and lower RH at the time of sampling. As far as we know, the association between type of upper layer and concentration of Der p 1 has not been described before and could lead to the formulation of practical advices in order to reduce HDMA concentrations on mattresses. 相似文献
996.
Factors influencing family physicians to enter rural practice: Does rural or urban background make a difference?
下载免费PDF全文
![点击此处可从《Canadian family physician Médecin de famille canadien》网站下载免费的PDF全文](/ch/ext_images/free.gif)
997.
BACKGROUND: Tinnitus is an uncomfortable symptom for the patient and an embarrassing one for the consulted physician. So far, there is no treatment that can be considered well established in terms of providing long-term reduction of tinnitus in excess of placebo effects. There is considerable evidence of pathophysiological similarity between tinnitus and chronic pain. Some forms of chronic pain can be treated by neurostimulation. OBJECTIVE: This study was designed to investigate the feasibility of neurostimulation of the cochlear nerve in order to reduce tinnitus. STUDY DESIGN: Pilot study. SETTING: Tertiary referral center. PATIENTS: Five patients with therapeutically refractory tinnitus were selected for this study. INTERVENTION: Placing a stimulation lead around the cochlear nerve through the suboccipital approach and connecting the stimulation lead to a pulse generator. MAIN OUTCOME MEASURES: The patients experienced 1) an absence of major or minor complications, such as death, meningitis, cranial nerve deficit, and vestibular problems; 2) tolerance of the procedure as considered by the patient; 3) relief of tinnitus in at least one patient. RESULTS: Implantation of the neurostimulation system was accomplished in each patient without any difficulty. None of the patients considered the treatment unbearable. No major or minor complications occurred in this study. Subjective tinnitus reduction was accomplished in four patients. CONCLUSION: Our preliminary data show that neurostimulation of the cochlear nerve is feasible, is bearable for the patient, and is a safe treatment modality without major complications. The effects on tinnitus are promising. 相似文献
998.
S C Zhang 《中华结核和呼吸杂志》1991,14(6):336-9, 376
Using the indirect immunofluorescent assay, we observed the variation of T-lymphocyte subsets of peripheral blood in 100 patients of primary bronchogenic carcinoma and 31 cases with active pulmonary tuberculosis. Serum CEA were measured simultaneously. The decrease of OKT3+, OKT4+, OKT8+ lymphocytes were significant in patients with lung cancer than that in healthy controls (P less than 0.01). The ratio of OKT4+/OKT8+ increased. It suggested that both cellular immunoincompetence and immunoregulatory abnormality were present in patients with lung cancer. After the resection of tumors 65 cases, the percentage of OKT4+ cells increased at the first week. Fourty seven cases were observed continuously for six months, it was found that OKT8+ cells increased (P less than 0.01). After anticancer chemotherapy, the patients with small cell carcinoma revealed a similar changes too. After operation and chemotherapy, serum CEA level decreased significantly too. 相似文献
999.
D Webber I P Braidman W R Robertson D C Anderson 《Journal of bone and mineral research》1989,4(6):809-815
Tartrate-resistant acid phosphatase activity (TRAPase) is widely used as a cytochemical marker to distinguish osteoclasts from macrophages and other related cell types. The degree of tartrate resistance, however, may depend on which reaction methods, tissues, or species are used. To investigate this further, we have measured the amount of cytochemical reaction product by microdensitometry. We compared osteoclast acid phosphatase (APase) activity in fresh frozen sections of neonatal rat calvaria using two different reaction methods; one is commonly employed for qualitative histochemistry and includes alpha naphthyl phosphate as substrate, simultaneous coupling to the chromagen Fast Garnet, and a 30-minute reaction time (method A). The other may be used to measure enzyme reaction rates in cells in situ and employs conditions suitable for initial velocity kinetics, namely naphthol-ASBI phosphate as substrate, post coupling to Fast Garnet, and a 2-minute reaction time. Although enzyme reaction rates differed greatly between the two methods, significant inhibition of APase activity by tartrate was observed in calvarial osteoclasts (69% and 59% with methods A and B, respectively), osteoblasts, and spleen macrophages. Using method B, mouse calvarial osteoclasts had similar APase activity to that seen in the rat. Tartrate produced little inhibition in these mouse cells, in contrast to the observations made with rat tissue, but murine spleen macrophages were significantly tartrate sensitive (40% inhibition with tartrate). On this basis, conclusions regarding the cell specificity of TRAPase should be treated cautiously. 相似文献
1000.
R Menapace W Binder C Skorpik H D Gnad 《Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift für Augenheilkunde》1989,198(3):129-134
Steady flattening of the tumor, increasing reflectivity and decreasing vascularity are echographic signs of successful irradiation treatment. The specific example of an irradiated choroidal melanoma shows that the absence of echographic changes by no means excludes tumor destruction. Because of a dense vitreous body hemorrhage, the melanoma could only be evaluated echographically. Since the echogram lacked evidence of regression, the tumor was locally resected 5 months later. Histology, however, revealed an amorphous mass of dead tissue pervaded by intact vessels. Apparently a successfully irradiated melanoma may generate an echo typical of vital melanoma tissue. The authors therefore draw the conclusion that only a steady tumor growth, as substantiated by an echogram, may be considered an unambiguous sign of tumor vitality. 相似文献